A version of GrandMaster's event and task systems (http://www.grandmaster.nu/blog/?page_id=261) with the dependency on Boost removed. A C++11 compiler is required, tested on a Mac with clang.
I received permission to put this code up on GitHub from GrandMaster under an MIT license. All attributions should be credited to GM. Both systems are part of GrandMaser's project, overdriveassault but in much different form. I suggest looking at the changes he's made to the systems.
I'm using a modified form of this code in my engine, I think both the event and taskmanager are great starting points. With the Boost requirement removed both systems are nearly drag-and-drop into any C++11 project.
All boost requirements have been removed. This includes changing boost::mutex to std::mutex and moving over to C++11 locking mechanisms. I also implemented a subset of boost::threadpool.
The largest change I made was removing the requirement for a dummy task if there are no tasks added. That was added to deal with the case not enough tasks were enqueued to wake a worker when the taskmanager shut down. I added a 1667 millisecond sleep to workers so when nothing can be done, they will wait a little bit and then check again. See line 136 in taskmanager.cpp.
The Makefile builds a very simple test application from test.cpp that does simple checks of the code. If bugs/improvements are ever submitted I'll add tests for them and improve test coverage.